Ready-reckoner.



ABRAHAM-GHA'IM SAMUEL-HIRSCH SGHABAD.

v READY RECKONER.

APPLICATION FILED 00T. 1a, 1009.

972,650. Patented 000. 11, 1910.

100000]- H2500 250.05 100000 H5000 '17537 500000 47.61500 11005 I00000naanoo 0001+ $00000 7.147.500 HHH 600000 $555000 H2011 100000 2957500165630 j.'

ABRAHM-CHAM SAMUF-li-HIRSCHJSCHABAD, OF BERLIN, GERMANY.-

READY-neuronas.'

Specification of Letters Patent.

Patented ct. itin-119i@ Application-tied October 18, 1909.- Serial No.523,295.

To atl whom it may concern:

Be it known that I, ABRAHAM-Granier SaMUnL-Hrnson SCHABAD, a subject ofthe Emperor of Russia.,` and resident of 22 .KlopstockstrasseJ Berlin,Germany,`have invented certain new and useful Improvements inVReady-Reckon'ers, of which the fol-lowing is a specification.

vThis invention relates to a new andim-v proved ready-reckoner whichshall enable the rapid change from one system of coinage into another tobe eieetedor the calculation of' the interest accumulated in any giventime at desired rates. It may also be used for other purposes for whichready-reckoners in tabular form are provided.

The reckoner yhereinY described is applicable to all decimal systems ofreckoning.

By means of the present invention t-he errors frequently arising fromthe use of tables are avoided and the position of the decimal point maybe very readily determined. Also the apparatus is very compact and maybecarried in the waistcoat-pocket.

The invention is illustrated inl one convenient form in the accompanyingdrawings in which-'- Y FigureA 1 is a longitudinal section through theapparatus, Fig.q2 a section on the line A-B of Fig. l. Fig. 3 is adetail-view of the end of the inner cylinder. Fig. et shows thedevelopment of the tables which are carried by the inner rotatablecylinder inFig.

l. Fig. 5 is a detailv-iew of the slidable cylinder on the outer-casing.Fig. 6 is a detail view showing the method of fixing the -removabletable carrying cyli-nder to the inner casing of the reckoner. Fig. 7illustrates the method of removing the inner cylinder from the outercylinder. Fig. 8 is an outside view of the entire apparatus.

In carrying the invention into eect according to the form shown an outercylindrical casing a is provided having a closed end b. To the closedend b there vis 'fixed axially a rod c. rlhe rod c carries two flat.springs d which open toward the closed end b.

Adaptedto rotate within the cylindrical casing' a and also to slidetherein, there. is a cylindrical casing e. The cylindrical casingA e hasat its righthand end in Fig. l an m-A wardly projecting ring or flange.f. By pushing the cylindrical casing e fromleft to right in Fig. l thesprings al are deflected inward to allow the ring f to pass. As soon asthe Aring f'passes the ends of the springs (Z lthese springs come tobear frictionally on the interior of the casing e. lt will be seen thatthe casing c may be rotated relatively to the casing a and also moveaxially within the outer casing a.. The springs (Z co-acting with thering j' however prevent the casing e from .being entirely 'removed fromthe casing a. 'Over the casing e there is passed a cylinder g having atable, such as illustrated .in Fig. 4f, printed thereon; The tableillustrated contains in the first column the numbers l, 2, 3, el and soon, each with 5 'eiphers The second `column represents the equivalentsin converting dollars into marks, that isin passing from the Germanmoney system into the United States money system. ln the third columnthere are the necessary figures for converting marks into dollars. Inthe outer casing a there are represented openings L, L, z' and j. Theopenings l1., 7L- are adapted to come opposite the first column whilethe opening z' comes opposite the second column and the opening j comesopposite the third column in Fig. L ln the openings t, z' and a smallpointer c is provided which shows the position of the point. By pullingthe cylinder e with the table g to the left in Fig. l, the position ofthe point lc is altered as desired. Thus in Fig 5 the decimal point c isindicated as representing 70.00 dollars and in the opening .i there isseen the number: 295.75 marks (on the basis 31002422.50). Thecommaprojections 7c are in the form illustrated fixed to the casing c.The opening it and the openingv are arranged in line and enablethetransferenee from marks to dollars 4open lefthand end of the casing cas seen in Fig. l. K

It will be understood' that by replacing i the cylinder g with anyothertables any desired kind of calculation may be effected with theready-reckoner herein described.

.To enable the casing e to be extracted for such removal and change ofthe cylinder g,

there is provided a tube pwhich is adapted.

to pass easily through the casing e and compress the springs Z so thatthe free ends of the springs come clear of the ring f. This is easilyeffected because the diameter of the tube p is smaller than the diameterof the tube e Aagainst which the springs d rest, therefore the tube pmay press the springs together when passing over same whereby the ring fmay pass over Athe springs and the tube e may be taken out. The casing emay then be extracted and the cylinder g changed as desired. An outershort cylinder g is also preferably passed over and fixed to rotate withthe outer casing a and this cylinder carries the inscription of the kindof reckoning being made. illustrated the cylinder g carries theinscript-ion Dollars, Marks where it comes opposite the openings h andz' and Marks Dollars in the line of the openings it and j.

It will be understood that when any'desired number of one system isrequired to be changed into another monetary system that the change mustbe effected in stages,

' thus if it were desired to convert 728 marks into dollars and centsthe operator Will first find the equivalent of 700 marks, then of 20marks, then of 8 marks, write these equivalents in a row and add themup. ,'Io facilitate the writing down and adding of these numbers thepencil 0 is provided.

I claim: 1. In an instrument of the kind described an outer cylindricalcasing having a plurality of openings therein, an inner casing rotatableWithin said outer casing and relatively slidable thereto, said innercasing being provided with rows of figures adapted to be brought insuccession under the openings in said outer casing, and a spring fixedto said outer casing and engaging frictionally Within said inner casing.

2. In an instrument of the kind described an outer cylindrical casinghaving a plurality of openings therein, an inner'casing rotatable withinsaid outer casing and relatively slidable thereto, said inner casingbeing provided with rows of ligures adapted to be brought in successionunder the openings in said outer casing, a flange on the end of saidinner casing and projecting inwardly thereof, and a V-shaped spring xedto said outer casing and frictionally engaging the walls of said innercasing, substantially as described.

3. In an instrument of the kind described Thus in the form.

-ralit of o eninvs therein an inner casin rotatable within said outercasing and relatively slidable thereto, said inner casing being providedwith rows of figures adapted to be brought in succession under theopenings in said outer casing, a ange on the end of said inner casingand projecting indesired, substantially as and for the purpose asdescribed.

4. In an instrument of the kind described an outer cylindrical vcasinghaving a plurality of openings therein, an inner casing r0- tatablewithin, said outer c'asingand relatively slidable thereto, a cylinderpushed over said inner casing and havin rows of figures thereon on itsouter surface, said igures being adapted to be brought in successlon`under the openings in said `outer casing', means for preventing relativerotation of saidinner casing and said cylinder carrying the jgures, aflange on the end of said inner casing and projecting inwardly thereof,a' V-shaped spring liXed to said outer casing and frictionally engagingthe walls of said inner casing and means for compressing the V-shapedspring to effect l and frictionally engaging the other and an outer tubeover said outer casing, said outer tube being provided with suitableinscriptions opposite the :openings in the outer casing and means forXing said outer tube to prevent relative rotation between said outertube and the outer casing.

In witness' whereof I have hereunto set my hand in the presence of twowitnesses.

ABRAHAM-CHAN SMUEL-HIRSCH SCHABAD.

Witnesses:

IVOLDEMA'R HAUPT, HENRY HASPER.

